Main Types of Energy Losses of Ultrarelativistic Pulsar Plasma in the Upper Layers of a Companion Star’s Atmosphere

The main types of energy losses experienced by ultrarelativistic electron-positron pulsar plasma in the upper atmosphere of a companion star are considered. These energy-loss mechanisms include ionization losses due to interactions with atoms of the medium, excitation losses associated with the energy transferred to plasma particles, losses resulting from the production of δ electrons, Cherenkov radiation losses, bremsstrahlung losses, synchrotron radiation losses, and inverse Compton losses. It is shown that the fastest component of the pulsar plasma can reach the top of the convection zone of the nearby companion star. The kinetic energy range of the plasma particles reaching the upper boundary of the convection zone corresponds to the energy range of the giant dipole resonance (GDR). As a result of the interaction between the pulsar plasma and the upper atmosphere of the companion star, localized regions of the photosphere and of the photosphere-convection zone boundary at different depths undergo nonuniform (spot-like) heating. This interaction may also produce neutron-rich isotopes, which are subsequently transported into the upper layers of the photosphere.